摘要：可再生能源发电系统通常在逆变器出口处接入LCL滤波器以抑制高频谐波,然而在LCL滤波器的参数设计过程中,不合理的参数设计会加剧系统中的谐波不稳定问题。因此,通过结合LCL滤波器的外特性需求,并且综合考虑系统稳定性对滤波器的约束条件,建立以谐波衰减率最大、电感成本最小以及系统稳定性最好为目标函数的LCL滤波器参数多目标优化模型。在模型的求解过程中,针对单目标优化算法和传统的多目标优化算法存在设计目标单一、收敛性差和优化效果不佳等问题,提出采用MOEA/D多目标优化算法来求解。该算法利用权重向量的进化导向性以及子问题邻域的优势共享特征,保证了算法对最优解的寻优能力以及在目标空间上的均匀分布,以获得理想的pareto最优前沿,并进一步采用模糊隶属度函数定量分析其优化效果。最后,利用Matlab/Simulink软件对光伏并网系统中的电压源型逆变器(Voltage Source Converter,vsc)进行仿真。仿真结果充分表明所设计方案的有效性和适用性。

摘要：The developments in power transmission via HVDC networks are fast,especially in Western Europe and *** challenges that we are confronted with are huge and considerable research and development efforts are *** attention is needed for high voltage direct current(HVDC)and ultra-high voltage dc(UHVDC)underground *** the highest voltage levels,we are still dependent upon classic technology based on mass-impregnated paper used in line commutated converter(LCC)***,more and more polymeric type cables are appearing on the market,as yet mainly for voltage source converter(vsc)*** financial,environmental and technical reasons the full focus is now on polymeric type cables,for use in LCC or vsc *** this paper,a closer look is taken at the interfaces in polymeric cable systems,*** the cables and in the cable *** the design process,we are challenged by the presence of interfaces from an electrical and thermal point of *** the field of electrical insulation,the interfaces between different materials are generally considered the weakest parts of the equipment and under DC stresses the situation becomes even more complex due to the charge dynamics at the ***,the design of(U)HVDC accessories has become a challenge if not a *** paper focuses on some of the important electrical and thermal aspects of interfaces in HVDC polymeric *** is discussed where we lack knowledge and where we may benefit from other scientific